Segment Information - Schedule of Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2018	Apr. 30, 2017
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	$ 255,945	$ 182,645	[1]
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	184,918	146,505
Rest of the world
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	$ 71,027	$ 36,140

[1] * Prior period information has been adjusted to reflect the adoption impact of ASC 606, which we adopted on February 1, 2018.